Acute Kidney Injury Basics

About Acute Kidney Injury

Early AKI Usually Does Not Cause Symptoms

AKI causes few symptoms until kidney function is almost gone. At that stage, as fluid and waste products build up in the
blood, a person with AKI can develop one or more of the following symptoms:

Pain in the hips and ribs

Fatigue

Loss of sensation in the hands and feet

A metallic taste in the mouth

Elevated blood pressure

Little or no urine output

Blood in the urine

Excessive urine production at night

Bloody stools

Nausea or vomiting

Decreased appetite

Seizures

Confusion

Swelling, especially in the legs, ankles and feet

AKI Incidence

Until recently, doctors lacked solid data about the incidence of AKI. So researchers at the University of California-San Francisco (UCSF) used a national database to tally the number of U.S. hospital patients with AKI severe enough to require dialysis between 2000 and 2009.

During that time span, the number of men and women who developed this most dangerous form of AKI increased annually, from 63,000 in 2000 to 164,000 in 2009, rising by roughly 10 percent each year. Nearly one in four patients who requires dialysis to treat an AKI dies.

When the UCSF team took a closer look at the data, some clear trends emerged. People with AKI requiring dialysis tended to be older (average age 63) and were slightly more likely to be male. Also, African-Americans had a higher risk for severe AKI than members of other racial groups. However, increases in AKI affected all demographic groups.

The authors of this study, published online in the Journal of the American Society of Nephrology in December 2012, offer several possible explanations for why AKI is becoming more common. For starters, our population is aging, and AKI becomes a greater risk as you grow older.

Not only are the number of cases of sepsis and acute heart failure rising, but hospitals are performing more medical procedures that appear to increase the risk for AKI, particularly cardiac catheterization (for diagnosing and treating heart disease) and mechanical ventilator use (for helping seriously ill patients breathe). Yet the UCSF researchers estimate that these influences account for only about one-third of AKIs.

Drug-induced Kidney Injury

Clear evidence shows that using certain medications may induce AKI, which researchers estimate contribute to about
one in five cases. That includes some drugs administered primarily in hospitals, such as certain types of contrast dyes injected into patients undergoing angiography (a type of x-ray used to examine the arteries).

However, some common medications such as the pain reliever ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with AKI, too. A large study published in BMJ in January 2013 found that people who
took NSAIDs during the same time they took two blood pressure–lowering drugsdiuretics plus either angiotensin
converting enzyme (ACE) inhibitors or angiotensin receptor blockersincreased their AKI risk by 31 percent, particularly
in the first 30 days.

The researchers didn't establish a direct cause-and-effect link between the drugs and AKI. But if you're taking both a diuretic and another blood pressure drug, be aware of the potential risks involved if you combine them with NSAIDs. Let your doctor know if you use NSAIDs; he or she may want to monitor your kidney health with blood tests.

Treating AKIs

Fortunately, AKI can often be cured when the underlying cause (such as an adverse reaction to drugs or infection) is diagnosed earlyespecially before dialysis is neededand treated, but it can take weeks or months for the kidneys to heal.

If you develop AKI, your doctor will give you medication to eliminate fluid and waste products from your blood and instruct you to eat a special diet. When severe cases require dialysis, treatment is usually only temporary. Even so, studies suggest that a bout with AKI increases the risk for developing chronic kidney disease later.

Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50